simple explaination of Darwin's theory of evolution

Today Jennifer asked us to write something we know about Darwin's theory of evolution. For sure, it's hard to explain in English so I go on internet and google it. The best explaination for Darwin's theory of evolution is natural selection and adaption. I knew that when i was studying biology in high school, Oberviously, in my first language. By the end of this topic, I hope I can use English to explain his idea more.